Hi Keith,

This dance is ugly, the alternative would have been to add a WT_SESSION_HOTBACKUP_LOCKED flag and use it similarly to the WT_SESSION_SCHEMA_LOCKED flag (i.e only take the lock if the flag isn't already set).

Making this change made me wonder how hotbackup works in the face of application drop calls. I looked through the code and it appears as though an application drop can proceed while a hotbackup is in progress. Am I missing something? Is that safe?